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MO: Fachverband Molekülphysik

MO 1: Biomolecules

MO 1.6: Vortrag

Montag, 14. März 2011, 11:45–12:00, TOE 317

IR spectra of microhydrated acetanilide cluster cations — •Matthias Schmies¹, Alexander Patzer¹, Kohei Tanabe², Mitsuhiko Miyazaki², Masaaki Fujii², and Otto Dopfer¹ — ¹Optik und Atomare Physik, TU Berlin, Germany — ²Chemical Resources Laboratory, Tokyo Institute of Technology, Japan

Acetanilide is one of the simplest aromatic molecules featuring a -NH-CO- peptide bond. We present IR photodissociation spectra of mass-selected complexes of the acetanilide cation microsolvated by a controlled number of ligands (L=argon, molecular nitrogen, and water). The IR spectra are analyzed by comparison with DFT calculations (M06-2X/aug-cc-pVTZ) and provide detailed information about the interaction potential (ligand binding site and interaction energy) between this prototypical biomolecular building block and polar/nonpolar ligands. Whereas Ar and molecular nitrogen preferentially bind to the aromatic ring, water exhibits hydrogen bonding to the acidic NH group of the amide moiety. The current work shows that ionization of acetanilide has a large effect on its charge distribution and its interaction with hydrophilic and hydrophobic ligands. In particular, the hydration environment is largely affected by the change in the charge distribution.